Bug 453597 - Monitor layout misidentified after screen energy-saving mode
Summary: Monitor layout misidentified after screen energy-saving mode
Status: RESOLVED DUPLICATE of bug 449285
Alias: None
Product: kwin
Classification: Plasma
Component: platform-drm (show other bugs)
Version: 5.24.5
Platform: Arch Linux Linux
: NOR minor
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: wayland
Depends on:
Blocks:
 
Reported: 2022-05-09 19:52 UTC by Nathaniel Mason
Modified: 2023-03-27 17:38 UTC (History)
2 users (show)

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Description Nathaniel Mason 2022-05-09 19:52:20 UTC
SUMMARY
Since updating to Kwin 5.24.5, my monitor setup may be misidentified after waking the screen up from energy-saving mode. This causes a whole bunch of issues and requires restarting the session to make it work properly again.

STEPS TO REPRODUCE
1. Open a plasma desktop Wayland session with a multi-monitor setup
2. Wait for screens to automatically enter energy saving mode
3. Wake up screen from energy saving mode

OBSERVED RESULT
Second monitor may be misidentified (In my case, this is either as "California Institute of Technology" or "unknown HDMI-A-1-unknown"). There are several other effects that may appear alongside this, most notably:
1. The panel will be present on the second monitor as if is was primary monitor, despite kscreen still reporting the main monitor being the primary
2. The primary monitor will turn black. Apps can still be dragged onto this monitor, but the desktop appears to no longer be present
3. The second monitor will scale itself up to the scaling used by the primary monitor (causing everything to appear excessively large)
4. The second monitor will lower it's frame rate from 144Hz to 60Hz

Any attempts to return the settings to normal while the secondary monitor is misidentified has no effect

EXPECTED RESULT
Screen layout after waking should be identical to the screen layout before entering energy saving

SOFTWARE/OS VERSIONS
Linux: 5.17.5-zen
KDE Plasma Version: 5.24.5-1
KDE Frameworks Version: 5.93.0-4
Qt Version: 5.15.3

ADDITIONAL INFORMATION
I have a very niche monitor setup. The primary monitor is my laptop monitor, which is 2880x1800@90Hz. Due to the high resolution, it is scaled at 150%. The second monitor is 1920x1080@144Hz, and requires no scaling. The second monitor is positioned diagonally above and to the left of the primary monitor. (In a style somewhat reminiscent of the Z tetromino)
Comment 1 Nate Graham 2022-05-10 16:21:48 UTC
Not actually as niche a monitor setup as you might expect. Except for the diagonal positioning part. :)
Comment 2 Zamundaaa 2022-05-10 17:50:23 UTC
This is probably a regression caused by https://invent.kde.org/plasma/kwin/-/merge_requests/2203
Need to figure out some workaround for the race condition
Comment 3 Zamundaaa 2023-03-27 17:38:40 UTC

*** This bug has been marked as a duplicate of bug 449285 ***